Lipase-catalyzed biosynthesis of cinnamoylated lipids in a selected organic solvent medium

Biosynthesis of cinnamoylated lipids through the lipase-catalyzed transesterification reaction of cinnamic acid with triolein was investigated in organic solvent media. Electrospray ionization-mass spectroscopy (ESI-MS) structural analysis of the reaction mixture revealed the formation of two major end products, monoleyl-1(3)-cinnamate and dioleyl-2-cinnamate. Decreasing the molar ratio of cinnamic acid to triolein from 1:1 to 1:4.5 resulted in an increase in the maximum bioconversion yield of cinnamoylated lipids from 19 to 42%, which remained constant at a lower ratio of 1:6. However, an excess of triolein appeared to have a more beneficial effect on the formation of dioleyl-2-cinnamate than monoleyl-1(3)-cinnamate, leading to different end product compositions at ratios of substrates. With cinnamic acid to triolein ratios of 1:4.5 and 1:6.0, an increase in the bioconversion yield of cinnamoylated lipids to 55% was achieved by adding 2.2 mgmL(-1) silica gel to the reaction mixture. Radical scavenging activity of cinnamoylated lipids, with 50% of radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, was found to be higher than that of its corresponding phenolic acid.